<template>
  <div>
      <router-link to="/" v-show="showAbs" >
      <div class="header-abs"> <div class="iconfont back-icon">&#xe624;</div></div>
      </router-link>
      <div class="header-fixed" v-show="!showAbs"
      :style="opcityStyle">景点详情
          <router-link to='/'>
      <div class="iconfont header-fixed-back">&#xe624;</div>
    </router-link>
      </div>
  </div>
</template>

<script>
export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opcityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop || document.body.scrollTop || window.pageYOffset
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opcityStyle = {opacity}
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  mounted () {
    window.addEventListener('scroll', this.handleScroll)
  },
  destroyed () {
    window.removeEventListener('scroll', this.handleScroll)// 对全局事件解绑
  }
}
</script>

<style scoped>
  .header-abs {
      position: absolute;
      left: .2rem;
      top: .2rem;
      width: .8rem;
      height: .8rem;
      line-height: .8rem;
      border-radius: .4rem;
      background: rgba(0, 0, 0, .8);
      text-align: center;
  }
  .back-icon {
      color: #fff;
      font-size-adjust: .4rem;
  }
  .header-fixed {
      z-index: 99;
      position: fixed;
      left: 0;
      right: 0;
      top: 0;
      overflow: hidden;
    text-align: center;
    height: 0.86rem;
    line-height: .86rem;
    color: #fff;
    background-color: #00bcd4;
    font-size:.32rem
  }
  .header-fixed-back {
      top: 0;
      left: 0;
      line-height: .86rem;
      position: absolute;
      width: .64rem;
      text-align: center;
      font-size: 16px;
      color: #fff;
  }
</style>
